1.As it turned out在句中为非限制性定语从句.其中It为形式主语,指代as所指代的成分.而非限制性定语从句中的关系代词as,就是代指后面的主句my little publication went on to become Student...再如：As we all know...as it turned out= it turned out (as)= it turned out (that my little publication went on to become Student, a national magazine for young people in the U.K.)没错，it作为形式主语，代替就是真正的主语（从句）：that my little publication went on to become Student, a national magazine for young people in the U.K.